1. Field of the Invention
The present invention relates to color measurement instruments, and more particularly to color measurement instruments capable of communicating in multiple protocols.
2. Description of Art
Color measurement instruments are capable of reading a color for the subsequent conversion of the color to a mathematical representation. That representation can be processed using techniques known to those skilled in the art to perform color functions such as calibration. Color measurement instruments include, by way of illustration and not limitation, spectrophotometers, colorimeters, densitometers, and spectroradiometers.
One particularly useful color measurement instrument is a monitor colorimeter (also known as a colorimetric radiometer) manufactured and sold by X-Rite Incorporated (X-Rite) of Grandville, Mich. as Model No. DTP92Q. This colorimeter is a tethered desktop unit for monitor calibration, and it includes a handheld unit and a cord for connecting the unit to the serial port of a computer. The handheld unit can be positioned over a portion of a monitor screen to read the color displayed on that portion of the screen. The color information or representation is communicated to the computer through the cord. The communication protocol for the colorimeter is RS232. The color information received by the computer from the colorimeter can be processed using color management software such as that sold by X-Rite under the trademark COLOR SHOP or that sold by Apple Computer under the trademark COLORSYNC.
While the DTP92Q colorimeter has enjoyed widespread popularity, it is dependent on the RS232 protocol. Although RS232 has been the serial communication protocol standard for a considerable period, computer manufacturers and the computer industry are developing new and improved protocols. For example, the Universal Serial Bus Implementers Forum (USBIF) recently developed a new protocol known as Universal Serial Bus (USB); and Apple Computer is phasing out the inclusion of RS232 serial ports on new computers. A unit such as the DTP92Q, which is capable of communicating only in the RS232 protocol, is not compatible with the USB protocol. Additional future changes in communications protocols are anticipated. For example, one such protocol is known as Fire Wire. Accordingly, it is possible that a colorimeter redesigned for the USB protocol may itself be outdated shortly.
The aforementioned problems are overcome in the present invention wherein a color measurement instrument is capable of multiple communication protocols each associated with a unique interface cable. The implemented protocol is selected by connecting the appropriate cable to the handheld unitxe2x80x94either during manufacture or during subsequent service.
More specifically, the color measurement instrument includes on-board hardware, firmware and/or software capable of communicating in a variety of protocols through a common internal connector. Any one of a variety of cables may be connected to the connector. Each of the cables is uniquely associated with a particular communication protocol and includes a connector interfitting with the connector within the instrument. Appropriate connections are made between the cable connector pin-outs and the on-board connector pin-outs so that the instrument communicates though the cable in the selected protocol.
In the disclosed embodiment, the instrument is capable of communicating in both the RS232 protocol and the USB protocol. A first cable is unique to the RS232 protocol, and a second cable is unique to the USB protocol. Either cable may be connected to the instrument, and particularly to the internal connector. After a particular cable has been connected, the instrument communicates in the selected protocol through the cable.
As will be appreciated, the present invention is not restricted to the particular protocols disclosed. The invention is readily extendable to other exiting protocols and to future communication protocols.
The present invention provides improved flexibility for color measurement instruments. With the exception of the cable, the instrument is xe2x80x9cgenericxe2x80x9d to all protocols. Only the cable varies by instrument to implement a desired protocol. The xe2x80x9cgenericxe2x80x9d design of the instrument simplifies manufacture, testing, and calibration. During manufacture, the instrument can be tested and calibrated using any one of the available protocols.
These and other objects, advantages, and features of the invention will be more readily understood and appreciated by reference to the detailed description of the preferred embodiment and the drawings.